template<class T, class Container = deque<T>>
	class queue//queue的实现
	{
	public:
		bool empty() const
		{
			return con_.empty();
		}

		size_t size() const
		{
			return con_.size();
		}

		T& back()
		{
			return con_.back();
		}
		const T& back() const
		{
			return con_.back();
		}

		T& front()
		{
			return con_.front();
		}

		const T& front() const
		{
			return con_.front();
		}

		void push(const T& val)
		{
			con_.push_back(val);
		}

		void pop()
		{
			con_.pop_front();
		}

		void swap(queue& x)
		{
			con_.swap(x.con_);
		}
	private:
		Container con_;
	};